Dream about late sister is a harbinger for your resourcefulness and survival skills. There is something in your life that you are not seeing clearly. You are protecting someone or something. The dream hints the relationship between the mind/mental and the body/physical. You are being taken for a ride.
Late sister dream expresses the elders around you. You feel like you are hot stuff. You are emotionally impoverished. This suggests female emotions and domination. You need to always be on the alert.
If you dreamt about late sister:
Talking would probably help, as you both need to share your feelings and see if you can get to the root of the problem. But what may be even better is getting out and doing something radically different and really exciting. Go for it!